Camshaft arrangements of this type are known as “cam in cam” systems. By means of these, it is possible for at least two cams of the camshaft—usually a number of respective cams—to be rotated relative to one another on the camshaft in order to vary the control times of the gas exchange valves of an internal combustion engine. Such camshaft systems are described for example in EP 1 945 918 B1, in GB 2 423 565 A and in WO 2009/098497 A1.
It is known to produce the rotationally fixed connection between the stator or a part thereof and the hollow shaft by means of a screw connection, such as is typical for the connection between the inner shaft and the rotor. A disadvantage of this solution is that it requires a relatively large radial installation space. This is a problem in particular if the internal combustion engine is of OHC (overhead camshaft) design. Furthermore, this connection increases the weight of the arrangement.
Furthermore, in camshaft adjusting systems, it has become known for the rotationally fixed connection to be produced by means of one or more pins which are pressed into the arrangement (in this regard, see GB 2 423 565 A, FIG. 1 and the pin 38 in said figure). Such a solution is however susceptible to component failure. Furthermore, with this solution, play may relatively easily form over the course of time, which manifests itself in wear and deformation of the components.
Accordingly, in generic adjusting devices, the connection of the hollow shaft to the stator constitutes a weak point which, in the event of failure, can lead to a malfunction of the camshaft arrangement.
The objective to be addressed by the present invention is that of further developing a camshaft arrangement of the type mentioned in the introduction such that the connection between the stator and the hollow shaft is improved. Here, in particular a radially space-saving solution should be sought since the available installation space is very limited.